Method of producing high resolution images and structure for use therein

ABSTRACT

A method of producing high resolution images formed of a plurality of small images produced by passing radiation through a collimated hole structure having substantially rectilinear small cross section passages. The collimated hole structure is provided with a high aspect ratio of passage length to passage cross section to provide a high resolution in the individual images produce thereby. A mask may be formed on one surface of the collimated hole structure having an opening exposing preselected ones of the collimated hole structure passages for producing a composite image defining a preselected pattern corresponding to the opening.

O United States Patent [151 3,678,564 Roberts et al. 51 July 25, 1972 [54] METHOD OF PRODUCING HIGH 3,380,817 4/1968 Gardner ..350/276 RESOLUTION IMAGES AND 3.356.854 12/1967 Humphrel.... .....350/96 STRUCTURE FOR USE THEREIN 3,526,885 4 1970 Roberts et all .317/230 3.5 6.636 l/l97l Roberts et al .;.96/36 [72] Inventors: John A. Roberts, North Chelmsford;

Alwyn sherbomi both of Mass' Primary Examiner-Norman G. Torchin 73 A i Brunswick Corporation Assistant Elraminer-Edward C. Kimlin Alrorney--Donald S. Olexa, Jerome M. Teplitz, John G. [22] Filed: Sept. 10, 1970 Heimovics and William G. Lawler, Jr. [21] Appl. No.: 70,952

ABSTRACT RltdU.S.A l t' Dt e a e pp [on a a A method of producing high resolution images formed of a DlVlSlQn of 3611 9 plurality of small images produced by passing radiation through a collimated hole structure having substantially rectilinear small cross section passages. The collimated hole 29/ 21095 structure is provided with a high aspect ratio f passage length n c I to passage cross section to provide a high resolution In the m- [58] Field of Search ..96/36, 350/95, 276, 3127424310, dividual images produce thereby A mask may be formed on 9 one surface of the collimated hole structure having an opening References Cited exposing preselected ones of the colllmated hole structure passages for producing a composite image defining a preselected pattern corresponding to the opening.

1 Claim, 11 Drawing Figures PATENTEU JUL25 1912 METHOD OF PRODUCING HIGH RESOLUTION IMAGES AND STRUCTURE FOR USE THEREIN CROSS REFERENCE TO RELATED APPLICATION part application Ser. No. 778,679, filed Nov. 25, 1968, and issued as US. Pat. No. 3,506,885 on Apr. 14, 1970, both applications being owned by the assignee hereof.

In applications such as micro-circuitry, it is desirable to provide images having a high resolution for subsequent etching. In the known structures, the resolution characteristics of the image producing means has been primarily controlled by the size of the openings of the screen utilized. The present invention comprehends an improved method and means for producing highresolution images wherein both openings size and aspect ratio of the openings are controlled to produce an improved image producing means.

Thus, a principal feature of the present invention is the provision of a new and improved method of producing high resolution images.

Another feature of the invention is the provision of such a method of producing high resolution images comprising the steps of forming a collimated hole structure defined by a body having a plurality of substantially rectilinear, parallel through passages opening through a spaced surface of said body, the passages having a maximum transverse dimension of under approximately 500 microns and having a preselected high aspect ratio of at least approximately to 1, providing on one of the surfaces a mask defining an opening having a preselected shape, the opening exposing a plurality of the passages, and passing radiation through the exposed passages to define a plurality of radiation images corresponding accurately to the cross sections of the exposed passages.

Still another feature of the invention is the provision of such a method of producing high resolution images comprising the steps of forming a composite defined by a metal matrix having a plurality of substantially rectilinear, parallel filaments formed of a different metal adapted to be leached from the matrix and extending to spaced surfaces of the matrix, the filaments having a maximum transverse dimension of under approximately 500 microns and a length between the surfaces of at least five times the maximum transverse dimension, providing on one of the surfaces a mask defining an opening having a preselected shape, the opening exposing the end of a plurality of the filaments, and leaching the filaments through the opening to define a plurality of passages defining an array corresponding to the shape of the opening, and passing radiation through the passages to define a plurality of radiation images corresponding accurately to the cross section of the passages.

Yet another feature of the invention is the provision of such a method of producing high resolution images wherein the mask comprises a plating layer.

A further feature of the invention is the provision of such a method of producing high resolution images wherein the mask comprises a developed radiation-resist layer.

A still further feature of the invention is the provision of such a method of producing high resolution images wherein the image is utilized in etching a sheet.

A yet further feature of the invention is the provision of such a method of producing high resolution images further ineluding the step of providing on the other of the spaced surfaces a second. mask corresponding to the first named mask having its opening aligned with the opening of the first named mask.

2 Another feature of the invention is the provision of such a method of producing high resolution images wherein the mask comprises a collimated hole structure having a relative large passage therein defining the opening.

Still another feature of the invention is the provision of such a method of producing high resolution images wherein the passages have a maximum transverse cross section of under approximately 10 microns.

Yet another feature of the invention is the provision of a ,.v

new and improved high resolution image producing device comprising a collimated hole structure defined by a body having a plurality of substantially rectilinear, parallel'through passages opening through spaced surfaces of the body..the

passages having a maximum transverse dimension of under approximately 500 microns and having a preselected high aspect ratio of at least approximately 5 to l, and a mask fixed to one of the surfaces and defining an opening having a preselected shape, the opening exposing a' preselected plurality of the passages for radiation transmission therethrough.

Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

FIG. I is a side elevation illustrating the first step in the forming of a collimated hole structure for use in an image producing device embodying the invention;

FIG. 2 is a vertical section illustrating a second step therein;

FIG. 3 is an enlarged isometric view of an element as formed by the process illustrated in FIG. 1;

FIG. 4 is a side elevation thereof with a mask layer provided on one end surface thereof;

FIG. 5 is an isometric view thereof illustrating a pattern of openings in the mask;

FIG. 6 is a diametric section illustrating a modified form of masked element wherein corresponding masks are provided on each of the opposite end surfaces;

FIG. 7 is an isometric view of a formed image producing device embodying the invention utilized for producing an image on a subjacent sheet;

FIG. 8 is a plan view of the sheet upon completion of the forming of holes therein in accordance with the pattern of FIG. 7;

FIG. 9 is a side elevation illustrating the use of a pair of collimated hole structures embodying the invention for cooperatively defining the image producing means;

FIG. I0 is an isometric view illustrating the use of a portion of the structure of FIG. 8 as a spinnerette; and

FIG. 11 is a view similar to that of FIG. 2 illustrating the formation of selected through passages in the element by means of a double masked structure as shown in FIG. 6.

In the exemplary embodiment of the invention as disclosed in the drawing, an image producing device, generally designated 10, is shown to comprise a matrix body 11 provided with a plurality of substantially rectilinear through passages 12. The image producing device 10 effectively defines a high resolution image producing device wherein patterns 13 are provided made up of a plurality of small images I4 of the passages 12, the patterns 13 corresponding to openings 15 in a mask 16 provided on the image producing device. As the passages 12 may have extremely small cross section and a relatively high aspect ratio, i.e. the ratio of the length of the passages to the maximum'cross sectional dimen sion thereof, the images produced thereby may be extremely high resolution images. n

The method of forming the image producing device 10 includes a first step, as illustrated in FIG. 1, wherein a plurality of rods 17 are sheathed in tubular sheaths l8 and bundled in an outer sheath, or can, 19 to define an assembly 20. The assembly 20 is constricted by suitable constricting means and herein, illustratively, is constricted by being drawn through a suitable die 21. The constricting process may be carried out in a plurality of steps to define a final reduced composite 22 wherein the rods 17 define very fine filaments 23 embedded in a matrix 24 comprising the original sheaths l8 diffusion bonded together by the constricting forces to define a substantially monolithic body 11. The composite 22 may be transversely cut as by a suitable knife 25 to define a plurality of disclike elements 26. y

a The rods 17 are preferably formed of a material differing from that of the sheaths l8 and can 19 to permit subsequent separation of the filaments 23 from the matrix 24 as by leaching. lllustratively, the rods 17 may be formed of monel metal, and the sheaths 18 and can 19 may be formed of stain less steel. Thus, the filaments 23 may be removed by treating the elements in a conventional nitric acid bath, generally designated 27, to dissolve the filament material leaving the stainless steel body 11 with a plurality of very small passages As the sheaths I8 become fusion bonded together and to the can 19, a substantially rigid monolithic body 11 is formed having high strength. By accurately controlling the rod and sheath sizes and the constricting steps, very high accuracy in the size disposition and configuration of the passages 12 may be obtained. Illustratively, the filaments, and thus the passages 12, may have a maximum cross sectional dimension of under 500 microns. As the filaments may be made as small as desired by the novel forming method, the passages may have extremely small maximum cross section, such as below microns down to submicron sizes. Further, as the filaments 23 support the matrix 24 in the cutting operation, the elements 26 may be made extremely small. The elements 26 may be cut by knife 25 to be relatively thin. However, the invention comprehends providing the image producing device 10 with passages having a relatively high aspect ratio, such as at least approximately 5 to l for improved resolution of the images 14.

The collimated hole structure 28 resulting from the leaching of the filaments from the elements 26 is illustrated in greater detail in FIG. 3. As shown therein, the passages 12 extend through the collimated hole structure to open through a front surface 29 and a rear surface (FIG. 4) 30. The mask 16 is provided on the surface 29 to define the openings corresponding to the image patterns 13. Illustratively, the mask may comprise a layer of material, such as metal, plated onto the surface 29 with suitable plating-resist material applied to the surface portion defining the openings 15. Thus, when radiation such as light is directed against one surface 29, or 30, of the image producing device 10, only those passages 12 exposed by the openings 15 will transmit light therethrough. As the passages have a relatively high aspect ratio and small cross section, the light passing therethrough may be used to produce dot-like images of extremely high resolution.

An alternative method of forming such an image producing device is illustrated in FIGS. 6 and 11 wherein the element 26 is provided with a first mask 31 on surface 29 and a similar mask 32 on surface 30. By indexing the respective masks to expose the opposite ends of the fine filaments 23 and removing the exposed filaments as by placing the plated element 33 in a suitable nitric acid leaching bath 34, passages 35 will be selectively leached with the unexposed filaments remaining in the matrix 24 to define an image producing device, generally designated 36, effectively similar to image producing device 10 The masks 3.1 and 32 may be formed by other suitable methods such as by exposing and developing a photoresist material to define the desired openings 15. Other methods of pgoviding the desired masks will be obvious to those skilled in t e art.

The image producing device 10 (36) may be utilized to provide high resolution images as for use in applications such as micro-circuitry, spinnerette, etc., applications. As shown in FIG. 7, the image producing device 10 may be utilized to provide images 14 on a photoresist layer 37 on a base such as metal plate 38. Upon development of the latent images 14 and subsequent leaching of the plate through the holes defined by the developed images, passages 39 may be provided in the plate 38 arranged in the patterns 13 corresponding to the l 'f hh sg as hown in FIGS. 7 and 8, where the openings 15 are T-shaped the patterns 13 of the openings 39 in plate 38 will be similarly T-shaped, with the individual passages therein accurately conforming to the accurately controlled cross sections of the passages I2 of the image producing device. Illustratively, such a pattern of holes 39 may be utilized in forming a spin nerette 40 to provide a T-shaped multi-strand plastic filament 41 as by extrusion in a conventional plastic extruder 42.

The invention further comprehends the use of a collimated hole structure to define the mask for selectively exposing preselected ones of the passages 12, such as in collimated hole structure 28. Thus, as illustrated in FIG. 9, a collimated hole structure, generally designated 43, having a preselected arrangement of relatively large passages 44, may be superimposed on collimated hole structure 28 to expose the desired passages 12 whereby the pattern defined by the passages 44 will be reproduced on the subjacent surface 45 by passage of radiation through the superposed collimated hole structures.

Thus, it may be seen that the collimated hole structure 28 provides means for defining high resolution images. The pattern of the images may be controlled by providing a mask on the collimated hole structure, or by superposing any one of a plurality of different masks thereon, including masks defined by other collimated hole structures. Any desirable pattern arrangement may be employed to expose different passages 12 so that an infinite variety of patterns may be obtained.

Accurate control of the resolution of the images 14 pro vided by the improved image producing device hereof permits the use thereof in forming extremely small images, such as used in micro-circuitry. The rigid strong characteristics of the collimated hole structures permits substantial reuse of the image producing devices while assuring maintained accuracy and control of the images produced thereby. As the masks may be formed integrally with the collimated hole structures, accurate reproduction of the images may be effected to provide a high degree of mask production accuracy.

While we have shown and described certain embodiments of our invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as defined in the appended claims.

We claim: v

1. A method of making a high resolution producing image device comprising the steps of:

a. providing a plurality of individually sheathed fine metal elements, the filaments and sheaths being formed of different metals;

b. orienting the sheath filaments in a parallel longitudinal 

1. A method of making a high resolution producing image device comprising the steps of: a. providing a plurality of individually sheathed fine metal elements, the filaments and sheaths being formed of different metals; b. orienting the sheath filaments in a parallel longitudinal relationship thereby defining a body having opposite surfaces at the ends of the sheathed filaments; c. diffusion bonding the sheathes to each other; d. securing to each of the surfaces a covering having a preselected shaped opening therein with the openings on each surface aligned with each other; and e. removing only those filaments aligned with the covering openings thereby forming a plurality of parallel passages defining an opening substantially similar to the openings in the coverings. 